diff --git a/flake.lock b/flake.lock
index 8e3730ffd..3b7dc9ed8 100644
--- a/flake.lock
+++ b/flake.lock
@@ -3,11 +3,11 @@
     "mozilla-overlay": {
       "flake": false,
       "locked": {
-        "lastModified": 1629225446,
-        "narHash": "sha256-HJX4Pc5ZUAg4apxB/XHuJ+6ukzvRQqeZMjscOBst2bA=",
+        "lastModified": 1634833229,
+        "narHash": "sha256-uDbVCkW91/AY87mTwm8XrX2E133LTFqwYsYNNxBcY9M=",
         "owner": "mozilla",
         "repo": "nixpkgs-mozilla",
-        "rev": "0510159186dd2ef46e5464484fbdf119393afa58",
+        "rev": "6070a8ee799f629cb1d0004821f77ceed94d3992",
         "type": "github"
       },
       "original": {
@@ -18,11 +18,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1634758644,
-        "narHash": "sha256-H3UW/msC6wadg28lcgZv2Ge/P7dWxesL6i37a0GOeyM=",
+        "lastModified": 1635946136,
+        "narHash": "sha256-y1l0FK/nyRqb9CCImHNDJYYTtCnSNF2rK5RFc+qaMEg=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "70904d4a9927a4d6e05c72c4aaac4370e05107f3",
+        "rev": "8429ae8722a319ebc26e9a38105e0797a824eb87",
         "type": "github"
       },
       "original": {
@@ -60,11 +60,11 @@
     "src-misoc": {
       "flake": false,
       "locked": {
-        "lastModified": 1634799783,
-        "narHash": "sha256-CbeXsLTwwYBWb5cfrVVYkcQYV207gi9+CQhzfeZbXGc=",
+        "lastModified": 1635235511,
+        "narHash": "sha256-XdBMBfup7JbUPzBi0An8GnQCIp7tiaczTrOwsPpvKCM=",
         "ref": "master",
-        "rev": "855914deace34880c69589022c52a8921f431063",
-        "revCount": 2375,
+        "rev": "34e545c190e08ada3f59712bdb71208ac6c39cbc",
+        "revCount": 2397,
         "submodules": true,
         "type": "git",
         "url": "https://github.com/m-labs/misoc.git"
@@ -82,11 +82,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1633622662,
-        "narHash": "sha256-AEWqSxdl2aIibv7vtU9vDMu8ytdOY10fwBaM77+Il64=",
+        "lastModified": 1635932388,
+        "narHash": "sha256-f8OEkvTqE3q+xgxjgO3Dnfi+neplozfJNrtBcPcMqg8=",
         "ref": "master",
-        "rev": "79d3c5caae79fe15f41d2b2248cad2344389555f",
-        "revCount": 340,
+        "rev": "36e4028f5bf4307b8deabcc3768af2708728cede",
+        "revCount": 387,
         "type": "git",
         "url": "https://git.m-labs.hk/M-Labs/nac3.git"
       },
diff --git a/flake.nix b/flake.nix
index 41e07c0e5..27f40c42d 100644
--- a/flake.nix
+++ b/flake.nix
@@ -77,7 +77,7 @@
 
         nativeBuildInputs = [ pkgs.qt5.wrapQtAppsHook ];
         # keep llvm_x and lld_x in sync with nac3
-        propagatedBuildInputs = [ pkgs.llvm_11 pkgs.lld_11 src-nac3.packages.x86_64-linux.nac3artiq sipyco ]
+        propagatedBuildInputs = [ pkgs.llvm_12 pkgs.lld_12 src-nac3.packages.x86_64-linux.nac3artiq sipyco ]
           ++ (with pkgs.python3Packages; [ pyqtgraph pygit2 numpy dateutil scipy prettytable pyserial h5py pyqt5 qasync ]);
 
         dontWrapQtApps = true;
@@ -94,8 +94,8 @@
           "--set FONTCONFIG_FILE ${pkgs.fontconfig.out}/etc/fonts/fonts.conf"
         ];
 
-        # FIXME: automatically propagate lld_11 llvm_11 dependencies
-        checkInputs = [ pkgs.lld_11 pkgs.llvm_11 ];
+        # FIXME: automatically propagate lld_12 llvm_12 dependencies
+        checkInputs = [ pkgs.lld_12 pkgs.llvm_12 ];
         checkPhase = ''
           python -m unittest discover -v artiq.test
           '';
@@ -190,9 +190,9 @@
             (pkgs.python3.withPackages(ps: [ migen misoc artiq ]))
             rustPlatform.rust.rustc
             rustPlatform.rust.cargo
-            pkgs.llvmPackages_11.clang-unwrapped
-            pkgs.llvm_11
-            pkgs.lld_11
+            pkgs.llvmPackages_12.clang-unwrapped
+            pkgs.llvm_12
+            pkgs.lld_12
             vivado
             rustPlatform.cargoSetupHook
             cargo-xbuild
@@ -309,9 +309,9 @@
           rustPlatform.rust.rustc
           rustPlatform.rust.cargo
           cargo-xbuild
-          pkgs.llvmPackages_11.clang-unwrapped
-          pkgs.llvm_11
-          pkgs.lld_11
+          pkgs.llvmPackages_12.clang-unwrapped
+          pkgs.llvm_12
+          pkgs.lld_12
           # use the vivado-env command to enter a FHS shell that lets you run the Vivado installer
           packages.x86_64-linux.vivadoEnv
           packages.x86_64-linux.vivado